使用@namedef 存储方程式

Question

这是此处问题的修改：@namedef 和数学模式。

我正在尝试定义一个名为的宏，myLabel该宏 1) 为方程式定义标准标签，2) 保存方程式，以便可以使用第二个名为的宏轻松重新打印displayEquation。 MWE 在这里：

\documentclass{article}
\usepackage{amsmath}
\usepackage{xstring}

%strip any alignment characters and display as an inline equation
\newcommand{\cleanLabel}[1]{$  \StrSubstitute{#1}{&}{} $ }

\makeatletter
\newcommand\myLabel[2]{%
  \label{#1}%
  \global\@namedef{label@store@content@#1}{#2}%
  #2}
\newcommand{\displayEquation}[1]{
    \cleanLabel{%
        \@nameuse{label@store@content@#1}%
    }
    }  
\makeatother


\begin{document}

Define three equations
\begin{align}
  \myLabel{simpleEq}{ f(x) &= 5x  } \\
  \myLabel{harderEq}{ f(x) &= \ln{5x}  } \\
  \myLabel{anothEq}{ \bm{a} &= \ddot{\bm{x}}}   
\end{align}
Equation \ref{simpleEq} has tag simpleEq, and I can display it inline as: \displayEquation{simpleEq}
\\
Equation \ref{harderEq} has tag harderEq,  and I can try to display it inline as: %\displayEquation{harderEq}  %FAILS
\\
Equation \ref{anothEq} has tag anothEq,  and I can try to display it inline as: %\displayEquation{anothEq}   %FAILS
\end{document}

当我有“简单”方程式时，宏可以正常工作。但是，如果我有任何带有反斜杠字符的方程式，它似乎会失败。有没有办法修改我的设置，以便它可以适用于更复杂的方程式？

Answer 1

问题是，它\StrSubstitute完全展开了它的参数，这可能不适用于所有内容。下面使用该expl3函数\tl_remove_all:Nn来删除 & 符号。

\documentclass{article}
\usepackage{amsmath}
\usepackage{bm}
\usepackage{xparse}

%strip any alignment characters and display as an inline equation
\ExplSyntaxOn
\tl_new:N \l_jpdomann_tmp_tl
\cs_new_protected:Npn \cleanLabel #1
  {
    $
    \tl_set:Nv \l_jpdomann_tmp_tl { #1 }
    \tl_remove_all:Nn \l_jpdomann_tmp_tl { & }
    \l_jpdomann_tmp_tl
    $
  }
\ExplSyntaxOff

\makeatletter
\newcommand\myLabel[2]{%
  \label{#1}%
  \global\@namedef{label@store@content@#1}{#2}%
  #2}
\newcommand{\displayEquation}[1]
  {%
    \cleanLabel{label@store@content@#1}%
  }  
\makeatother

\begin{document}

Define three equations
\begin{align}
  \myLabel{simpleEq}{ f(x) &= 5x  } \\
  \myLabel{harderEq}{ f(x) &= \ln{5x}  } \\
  \myLabel{anothEq}{ \bm{a} &= \ddot{\bm{x}}}   
\end{align}
Equation \ref{simpleEq} has tag simpleEq, and I can display it inline as: \displayEquation{simpleEq}
\\
Equation \ref{harderEq} has tag harderEq,  and I can try to display it inline
as: \displayEquation{harderEq}  %FAILS
\\
Equation \ref{anothEq} has tag anothEq,  and I can try to display it inline as: \displayEquation{anothEq}   %FAILS
\end{document}